The present invention relates to a pressure regulator and in particular to a pressure regulator for use with pressure fluid-operable brake systems.
Pressure regulators are employed, for example, in an automotive vehicle brake system to distribute the brake pressure between front and rear axles in response to load. The German Patent DE-OS No. 30 01 415 discloses a load-sensitive brake force regulator of this type, wherein a reduction in force is achieved through an enclosed rubber element which applies force to a transmission member through a predetermined proportion of its surface to actuate the valve in an opening direction. This device has a particular shortcoming. Namely, although due to the load exerted on the vehicle suspension spring, the rubber element does move the valve means in the opening direction, no return movement for closing the valve is possible. A further shortcoming of this device is found in the fact that the rubber element, in the course of time, changes its characteristic thereby precluding precise regulation.